U.S. Pat. No. 5,404,671 (Farrow, Kumar and Mitchell), assigned to the assignee of the present invention, discloses a method for producing sod and the sod resulting therefrom, which utilizes a root support matrix comprised of shredded, recycled carpet pieces and compost. This patent recognizes the desirability of a source of slow release plant nutrients in the sod.
U.S. Pat. No. 5,224,292 (Anton), assigned to the assignee of the present invention, also recognizes the desirability of slow release plant nutrients. This patent discloses a fibrous mat for growing plants which includes a layer of hollow synthetic fibers having in their lumens water-soluble plant adjuvants.